Permian
:See also: (Day 4) Permian or Permian period is a period in that dates from 298.9 Ma to 251.902 Ma. The Permian was a time of great changes and life on Earth was never the same again. By the beginning of the Permian, the motion of the Earth's crustal plates had brought much of the total landmass together, fused in a supercontinent known as Pangea. Interior regions of this vast continent were probably dry, with great seasonal fluctuations. There are indications that the climate of the Earth shifted during the Permian, with decreasing glaciation as the interiors of continents became drier. }} By the , it experienced three mass extinctions that may have all been related within a 21 million year time-span: starting with Olson's Extinction in 273 Ma, followed by the end-Cap extinction in 260 Ma, and ending the period with the worst in Earth's history—the P-T extinction in 252 Ma. ;Climate changes The in the Permian was quite varied. At the start of the Permian, the Earth was still in an , which began in the Carboniferous. Glaciers receded around the period as the climate gradually warmed, drying the continent's interiors for thirteen million years. In the period, the drying continued although the temperature cycled between warm and cool cyclesPalaeos: Life Through Deep Time > The Permian Period Accessed 1 April 2013. for another eight million years s in marine Capitanian showing an increase in δ13C values. The change in carbon isotopes in the sea water reflects cooling of global climates.Isozaki, Yukio. "A Unique Carbon Isotope Record across the Guadalupian-Lopingian (Middle-Upper Permian) Boundary in Mid-oceanic Paleo-atoll Carbonates: The High-productivity "Kamura Event" and Its Collapse in Panthalassa." ScienceDirect (2006): 21-38. Web. This climatic cooling may have caused the end-Capitanian extinction event ( ) among species that lived in warm water, like larger s (Verbeekninidae), large s (Alatoconchidae) and corals, and Waagenophyllidae.}} until the period ended by P-T extinction. ;Environmental changes The mid-Permian period experienced a hiatus in stratigraphy as related to a series of events that may have been caused by sudden environmental changes. Pangaea's continental interior began drying due to a warm zone event that spread in the northern hemisphere. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun, on surfaces devoid of vegetation cover. A number of older types of plants and animals died out or became marginal elements. The results of which became known as Olson's Extinction in 273 Ma. This was the first mass extinction of this period, followed by the end-Cap extinction. The resulting extinctions were realized across many groups, including plants, marine invertebrates, and tetrapods. Extreme environments were observed from the Permian of Kansas which resulted from a combination of hot climate and acidic waters particularly coincident with Olson’s Extinction. Fauna did not recover fully from Olson's Extinction before the emergence of the Permian-Triassic extinction event. Estimates of recovery time vary, where some authors indicated recovery was prolonged, lasting 30 million years into the Triassic. See also * Life expansion Notes References ;Further reading * Jin, Y.-G., B.R. Glenister, C.K. Kotlyar, and J.-Z. Sheng. 1994. An operational scheme of Permian chronostratigraphy. Palaeoworld 4:1-14. * Jin, Y.-G., S. Shen, C.M. Henderson, X. Wang, W. Wang, Y. Wang, C. Cao, and Q. Shang. 2006. * The global stratotype section and point (GSSP) for the boundary between the Capitanian and Wuchiapingian Stage (Permian). Episodes 29(4):253-262. * Jin, Y.-G., Y. Wang, C. Henderson, B.R. Wardlaw, S. Shen, and C. Cao. 2006. The global boundary stratotype section and point (GSSP) for the base of Changhsingian Stage (Upper Permian). Episodes 29(3):175-182. * Jones, T.S. 1953. Stratigraphy of the Permian Basin of West Texas. West Texas Geological Society Publication 53-29. 63 pp. * Menning, M. 1995. A numerical time scale for the Permian and Triassic periods: An integrative time analysis. Pp. 77-97 in P.A. Scholle, T.M. Peryt, and D.S. Ulmer-Scholle (eds.), The Permian of Northern Pangea, Vol. 1. Springer-Verlag, Berlin. * Ross, C.A., and J.R.P Ross 1995. Permian sequence stratigraphy. Pp. 98-123 in P.A. Scholle, T.M. Peryt, and D.S. Ulmer-Scholle (eds.), The Permian of Northern Pangea, Vol. 1. Springer-Verlag, Berlin. Category:Theoretical History Category:1.6 Ga–66 mya